A bottomless portafilter exposes the basket, so small jets that a spouted housing might collect can reach your counter. Uneven flow through the coffee is one possible cause, but spray is not a precise diagnosis on its own. Start by finding where the water or coffee escapes.
Basket jets or a leak around the rim?
Jets from the basket holes call for a check of preparation, grind and basket condition. Water escaping around the outside of the portafilter calls for a different check: seating, grounds on the rim, compatibility or the group gasket.
If the handle feels insecure or hot water leaks around it, stop the shot. Let the machine release pressure according to its instructions before removing the portafilter. Do not tighten or remove it while brewing. For the Bambino Plus, consult Breville's operating and troubleshooting instructions; use the manual for your exact model if it differs.
Reset the basket and puck preparation
Start with a clean basket and inspect the holes for residue or visible damage. Rinse and clean it as the manufacturer directs; do not enlarge holes to cure a jet. Confirm that you are using the intended basket type. A dual-wall basket's restricted outlet behaves differently from the exposed hole field of a single-wall basket.
Weigh a dose within the basket's stated guidance. Spread the grounds evenly, break up clumps if present and tamp level. Avoid knocking the side of the basket after tamping. A flat-looking top does not guarantee even density throughout the coffee bed.
Use a repeatable recipe to check the grind
Hold dose and beverage weight steady for comparisons. An illustrative starting recipe for an appropriate double basket is 18g of coffee and 36g of espresso, a 1:2 ratio. It is a starting point, not a requirement for every bean or basket.
Record elapsed time from the same point each time, such as when you start brewing. If the shot rushes to the target yield, try a slightly finer grind after checking preparation. If flow nearly stops, try slightly coarser. Follow your grinder's adjustment instructions and change one variable at a time.
A fixed number of seconds cannot guarantee good extraction. Different pre-infusion settings, coffees and baskets can produce different useful timings. Taste the result before deciding whether another adjustment helped.
Check dose, coffee and hardware
Overfilling can disturb the puck when locking in. Use the basket and machine's dose guidance, and recheck clearance if you add a puck screen. Very recently roasted coffee can behave differently as it releases gas; follow the roaster's resting advice instead of treating one resting period as universal.
If a persistent jet remains in the same area, inspect that part of the basket for residue or damage. If the problem is at the rim, compare fit with the original portafilter and consult the machine's maintenance guidance.
What a bottomless view can tell you
Use the view beneath the basket to compare shots, not to certify flavor. One central stream does not prove even extraction, and an occasional droplet does not automatically make a shot bad.
The Creamore 54mm detachable-spout portafilter lets compatible Breville owners observe the basket in bottomless mode and use the spout when directing the pour is more convenient. Reattaching the spout may contain the mess, but preparation and fit problems still need attention. For unresolved rim leaks or compatibility questions, contact Creamore with your exact machine model and product details.